Air heater



P. J. TIMBERLAKE June 14, 1938.

AIR HEATER 2 Sheets-Sheet 1 Filed Oct. 16. 1936 Fkul L]. Timberlake June14, 1938. P. J. TIMBERLAKE AIR HEATER Filed Oct. 16,-1956 2 Sheets-Sheet2 Raul filler-1m 1 a Patented June 14, 1938 UNITED. STATES PATENT OFFICE6 Claims.

The present invention relates to improvements in portable air heaterconstruction and has particular-referenceto air heaters especiallyadapted for use in connection with the service of automobiles and thelike. While concerned broadly with apparatus for heating and discharginga stream of airunder pressure; the design of the present invention asherein illustrated is particularly suitable for the uses advocated inUnited States .Patent No. 1,997,039 of the air heater disclosed therein.

Briefly my improved heater construction comprises a portable frameworkwithin which is supported a removable carrier supporting one or -moreresistance heat elements. At one end of the framework, structure isprovided for connecting the interior of the heater with a source of airunder'pressure while at the opposite end a nozzle distributes the heatedair as it leaves the chamber surrounding the carrier-for the resistanceelement. One aspect of the invention consists of'the novel arrangementof the parts going into the construction of the-framework of my heater.which expedites assembly and reducescost of production. Another ispresent in the novel construction of the removable carrier supportingthe resistance heating. element which-gives efflcientand rapid heatingof the air and prolongs the life of the heating element. Other features.of the invention include the air coupling and air adiustmentstructures.

In ;the drawings:

Fig.4 is a side elevational view partly shown in broken cross-section'of one form of air heater embodying the present invention,

Fig..2 is a cross-sectional view through the barrel ofthe air heatertaken on the line IIII ofwFig; 1,

Fig.3 is a fragmentary side elevational .view of the clamping yokeshowing its adjustability for various sizes of air chucks,

Figs. 4 and 5 are side elevational views of modified types of attachmenttips,

Fig. 6 is a cross-sectional view of a stepped conical shaped collar foruse in connection with the attachment tip,

Fig. '7 is a cross-sectional view of another form of tip to be used withthe air heater,

Fig. 8 is an end view of the carrier with an insulated spacing ringconnectedthereto,

Fig.- 9 is a vertical cross-sectional view taken on :the center line ofFig. 8,

Fig. .10 is a fragmentary cross-sectional view similar to Fig. .1 ofanother form of barrel and assembly construction with the carrierconstruction shown in Figs. 8 and 9 shown in assembled position,

Fig. 11 is an end view partly shown in crosssection of the barrelconstruction showing mechanism for controlling the heat and air supplyto the heater, and

Fig. 12 is a broken perspective view showing a suitable arrangement forcontrolling the heating capacity.

In the form of the invention illustrated in Fig. 10 1 the heater l0comprises a cylindrical barrel generally designated l2, headers I4 andiii, a handle l8 and a nozzle 20. The barrel i2 is preferably fabricatedfrom a tube 22 of expanded metal concentrically disposed in spacedrelation 15 from a sheet metal tube 24. Likewise concentrically arrangedwithin and spaced from the tube 24 is a tube 26, the space between thetubes 24 and 26' is shown as filled with a suitable insulating materialsuch as loose asbestos. Support 20 is given the spaced tubes 22, 24 and26 through cylindrical shoulder portions upon the headers l4 and I6which are preferably of cast metal. Opposed conical recesses 28 and 30are provided in the headers i4 and Hi to support opposite ends 25 of thecarrier 32 upon which is wound the electrical resistance heating element34. The tubes 22, 24 and 26 and the carrier 32 are maintained in theirassembled relation by screws 36 or other suitable fasteninginstrumentalities securing the 30 ends of thetube 22- to the headers l4and 16. By removing the screws 36 all the parts supported between theheaders I4 and I6 may be removed. This arrangement enables the parts tobe readily replaced and greatly simplifies the assembly and 35 reducesthe cost thereof. The specific construction of the carrier 32 and themanner in which the heating element is wound thereon is an importantfeature of the invention. As shown in Figs. 1 and 2 the carrier 32 has afluted outer 40 surface upon which the heating element 34 is spirallywound. Preferably the ridges 38 between adjacent flutes are notchedalong an interrupted spiral path to receive the element 34 thuspreventing the same from shifting axially 45 of the carrier 32 duringuse. With such a construction as will be clearly understood from Fig.

2, the major portion of the heating elements 34' will be spaced from thesurface of the carrier 32 affording access of the air to be heated toall 5 sides of the heating element 34 spaced between the ridges 38. Theterminals for the heating elements 38 are shown at 4|] and 42. Toexpedite the. winding of the carrier 32 and to avoid imbedding anyportions of the same, an axially 55 extending groove 44 is providedalong which the heating element extends from the terminal 40 to the leftend of the carrier 32 as viewed in Fig. 1 to the starting point of thespiral Winding extending back to the terminal 42. The carrier 32 may beof any suitable insulating material and is preferably molded as anintegral section. A suitable electrical connector 43 extends through aseal (not shown) in the header I6 and is connected to the terminals 49and 42. The connector 43 in most cases will be provided with a suitableplug for connection to the electrical outlet. As the recesses 28 and 30in which the carrier 32 is supported merge with the air outlet :35 andair inlet 48, respectively, it is desirable to bevel the ends of thecarrier 32 as at to provide adequate opening for the passage of air. Inproduction the carrier 32 is loosely supported in the recesses 2d and 36so as to provide for any expansion. that may take place upon heating andthus avoiding any warping of the carrier 32 or distortion or looseningof the barrel I2.

The outlet 36 is threaded to receive various nozzles and conduitstructure. As illustrated in Fig. 1 a nozzle 2?: is provided which isparticularly adapted for use in connection with the warming of grease tobe removed from a differential housing of an automobile. A tip 52 isthreaded into the end of the nozzle 25 for insertion into the usualopening in the differential housing. The conical shaped plug 54functions to seal such opening under the stress of the spring 58 so asto assist in developing a pressure within the housing for forcing theWarm grease from the differential through the drain opening. The tip 52is preferably deflected at right angles to the axis of the connectorplug 54 to enable the tip to be hooked behind the adjacent wallstructure defining the opening in the differential housing.

As the heater shown in Fig. 1 is particularly designed to be used ingarages and service stations for automobiles equipped with air pressure,the heater I6 has an integral projection 53 upon which there is provideda seat 60 for an air chuck t2 of well known construction imposed in theair line 66. For clamping the chuck E2 to the seat a yoke 6t is providedin which a thumb screw 68 is carried for engaging with the chuck Toaccommodate the various size air chucks that are found in use on themarket the yoke as shown in Fig. 3, has a plurality of verticallyaligned openings iii in which the attachmerit screws l2 may beselectively inserted to fasten the yoke 68 to the projection 58 invaried adjustment with respect to the position of the screw 68 withreference to the seat 69. The seat 66 embraces an opening M whichcommunicates with the chamber l6 opening into the recess 48. Admissionof air and regulation of the quantity of air to the heating chamber iscontrolled by an. adjustment screw I8 threaded in the projection 58 at8B. The end of the screw I8 is shown reduced at 82 to engage and liftthe poppet valve 84 from its seat to permit fiow of air through the airline 64 into the interior of the heater. By regulating the screw 18 theamount of air admitted past the valve 85 may be controlled. The path ofthe air through the heater and nozzle 20 is indicated by the arrows.

In Fig. 4 a modified form of tip 86 is shown which is threaded into thenozzle 20 in a manner similar to that shown in Fig. 1 but in lieu ofbeing angularly disposed to the axis of the conical plug 5t it isprovided with an integral projection 88 which engages back of the wall98 adjacent the wall structure defining the opening 82 which may be thatfound in the differential of an automobile. The tip arrangement 94 shownin Fig. 5, in lieu of the integral projection 88, a rivet 9% has beenpassed through the end of the tip 94 to provide a suitable hookingconstruction for engagement with the wall structure adjacent the openingthrough which the tip may be inserted. A modified construction B8 isshown in Fig. 6 which in lieu of having a smooth conical surface as theplug 54 a series of stepped circular shoulders I96, I02 and I M areprovided equipped with gaskets Hi8 to enable the plug to be used withvarious size openings and give a more effective air seal than may befound pos-- sible with the conical plug 54. In Fig. '7 a tipconstruction I08 is shown which may be threaded into the nozzle 29 inthe manner of the tip 52 where it is desirable to spray the heated airagainst an object to be warmed up or thawed out. To get a gooddistribution of the air the tip I08 may have slots H0 and H2 at rightangles to fan out the air as it passes through the nozzle.

In Figs. 8 and 9 an insulating ring II9 of nonabsorbing material such asmica, porcelain and the like is shown fitted over an end of the carrier32 for the purpose of further insulating the electrical heating elementfrom the cast headers I4. This precaution may be advisable in caseswhere the carrier 32 is made up from a molded insulating materialcontaining asbestos or similar material which may absorb sufiicientmoisture to become a conductor. As will be understood a ring II9 will beused at opposite ends of the carrier 32. In Fig. 10 the modified carrierconstruction in Figs. 8 and 9 is shown supported in position upon one ofopposing headers I23 provided with circular slots I28 and internallythreaded circular slots I30. In assembling the parts defining the barrelconstruction the expanded metal tube I32 is merely inserted in the slotI28 and with the insulating rings H9 at opposite ends of the carrier 32loosely received in the opposed recesses I 34 the tube I36 is threadedinto the headers I26 which will tie the headers and barrel definingparts together in assembled relation. In lieu of having two sheet metaltubes for defining the space in which the insulating material is housedas shown in the construction of Fig. l a molded tube I33 of suitableinsulating material is shown externally supported within the tube I 36but without any internal support other than its own bond. I have alsofound it practical to use the insulating tube I38 without the supportingand shielding tube I 36 :and holding the parts in assembled relation inthe manner shown in Fig. 1. Such a construction may be very cheaplymanufactured as the heater would consist primarily of an insulatedcarrier for the heating element and a tube of insulated materialdefining a chamber within which the carrier is supported by theperforated metal outer shield and spaced headers.

As it is desirable that air be circulated to the heating chamber at alltimes while the heating element is in a closed electrical circuit toavoid overheating, one suitable arrangement is shown in Fig. 11 foraccomplishing this result and making it impossible for the operator toclose the electrical circuit in which the heating element is locatedwithout first having air under pressure flowing through the heatingchamber. As illustrated H8 and I20 correspond to the projection B andthe header I 6 of the construction shown in Fig. 1. The heaterconstruction is shown adapted to-a different forrnof air chuck from--that shown'in'Fig. 1 in which the connection is off and adjustmentneedle valve I24.

"made a bayonet lock. As shown the male member I-I4 carrying a couplingpin is threaded at 'I I6 into the projection I'I8. 'With this type ofair chuck at the time the air line is coupled to the-pressure in theconduit I I9 is a piston having a conical head I70 and a body portionI'I4 supported for movement in a bore I13. The piston is looselysupported-in the bore I13 and is lightly held in a raised position by aspring I12. When air under pressure is passing through the cham ber I ISthe piston will be lowered until the conical head I10 engages with acomplementary seat I'I5 to seal the bore I13. This movement willposition a reduced portion I'I'I of the piston in alignment with the pinI66 connected to a slide I19 reciprocated by movement of the button I68of the toggle switch I64 of well known construction. With thisconstruction it will become apparent that the button I68 can only berocked to the on position when the air pressure is on and the restrictedportion I'I'I is in alignment with the pin I66. It will be understoodthat the switch I64 is located in the electrical circuit in which theheating element is contained.

In Fig. 12 is shown an arrangement which may be used in connection withmy improved heater if it is desired to have a regulation in heatingcapacity. This may be accomplished by winding the carrier I39 with twoseparate resistant heating coils I40 and I42 longitudinally spaced alongthe carrier I39 and terminating in spring terminals I44 and I46,respectively, these terminals being supported on the surface of thecarrier I39. As in the case of the carrier 32, the carrier I39 is shownfluted and provided with longitudinally extending grooves I43 throughwhich the electri cal resistance elements are passed for insulating theterminal ends of the heating coils and for spacing the separate heatingelements from each other. Suitable spring terminals I50 connect with thelead-in conductors I52 which may extend to the switch I64. Forselectively connecting the elements I40 and I42 into the electricalcircuit either in parallel, together or separately, or in series witheach other to give high, low and intermediate heat, a contact drum I 54is provided which may be in the form of a bushing of insulating materialpressed over a metal core I56 which extends through the wall of theheader I58 and has connected at the outer end a button I60 which may bemanually turned to selectively rotate the drum I54. For placing theelements I40 and I42 within the electrical circuit suitably arrangedcontactor plates I62 are secured to the surface of the drum I54 whichupon rotation of the drum I54 through the turning of the button I60 arebrought into engagement with the spring terminals I40, I46 and I50 intheir proper sequence to give high, low and medium heats. Preferably theconductors I52 have a suitable snap switch such as I64, as shown in Fig.11, interposed between the terminals I50 and the electrical outlet so asto avoid any arcing that might result from the type of switchconstruction shownin Fig. 12 if the same were employed to make and breakthe electricalcircuit.

-It is to be understood that the construction shown in Fig. 1 isextremely simple and effective in operation and may be manufactured andmarketed at relatively low cost. The control of the heating capacity-bythe construction shown in Fig. 12 and the safety structure shown in"Fig. 11 may be included if desired but are not essential for successfuloperation of the heater.

I claim:-- '1. In an'air heater of the class described, an elongated airchamber through which air to be a heated is directed, walls at oppositeends of said chamber having recesses defined therein, air inlet anddischarge passages defined in said walls and opening into said recesses,a carrier supported at opposite ends of said recesses and in saidchamber having ridges defined on the surface thereof, said carrier andrecess being so shaped as to direct the air flow along the outer side ofsaid carrier and an electrical heating element imposed over and bridgingsaid ridges so as to space the major portion of said element from thesurface of said carrier and to dispose the same into the air streamthrough said chamber.

2. In the heater of the class described, a pair of end members havingcentrally disposed recesses therein, a carrier member having anelectrical heating element supported thereon directly and axiallysupported from opposite ends in said recesses, an air inlet opening intoone of said recesses and an air outlet opening out of the other of saidrecesses, means for directing air to and from said inlet and outlet,said carrier being removably supported, said carrier and recesses beingshaped to provide openings directing the air flow substantiallyuniformly along the outer side of said carrier, and means supportingsaid end members in spaced relation and defining a chamber about saidcarrier.

3. In an air heater of the type described, an air inlet including a seatembracing the outer end of said inlet and adapted to receive an airchuck, means disposed over said seat, an adjustable clamp supported insaid means and adapted to be brought into engagement with an air chuckto hold the same to said seat, an adjustment screw adapted to engagewith the valve of an air chuck supported on said seat to open the sameand regulate the amount of air admitted to the heater, and meanssupporting said adjustment screw for movement relative to said seat.

4. In an air heater of the type described, spaced end members, a centralheating unit entirely and directly supported from said members,-anonmetallic tube of insulating material embracing said unit in spacedrelation throughout and defining therewith an uninterrupted tubularchamber, shoulder portions upon said members for supporting said tubeindependently of said unit, and an outer metal tube for spacing the saidmembers and for holding said members and insulating tube in assembledrelation, said insulating tube being relieved of all structural functionby said metal tube and being shielded thereby, said insulating tube andunit being assembled and disassembled through relative spacing of saidmembers.

5. In an air heater, the combination of a heating chamber, a conduit forconducting air under pressure into said chamber, means actuated by airpressure and moved from one position to another thereby, manuallyactuated switch mechanism, and means actuated by said switch andcoacting with said first means resisting movement of said switch withsaid first means in one position and being ineffective to resistmovement of said switch in another position.

6. A heater of the type described comprising a pair of separate verticalend members, centrally located axially aligned recesses defined in theinner opposed faces of said members, shoulder portions concentric withsaid recesses defined outwardly therefrom in said faces, one of saidmembers having an air inlet opening through its wall into one of saidrecesses, the other of said members having an air outlet extendingthrough its wall out of said other recess, an elongated electricalinsulating core of substantially uniform cross section having itsopposite ends directly engaging and supported in said recesses, saidcore having telescoping engagement within the recesses of said memberswhereby assembly may be efiected merely by axial displacement of saidmembers, an electrical heating unit upon said core, an elongated heatinsulating tube in which said core is concentrically located, said tubelikewise having telescoping relation at opposite ends with said shoulderportions and assembled in the manner of said core, said tube formingwith said core an elongated chamber of unobstructed uniform crosssection into which said heat unit projects, said recesses and said corebeing shaped to provide air passages between the ends of said core andthe defining walls of said recesses whereby the air flows uniformlyalong the outside of said core in entering and 15 leaving said chamber.

PAUL J. TIMBERLAKE.

